Path: utzoo!attcan!uunet!aplcen!uakari.primate.wisc.edu!uwm.edu!cs.utexas.edu!rice!dboyes
From: dboyes@rice.edu (David Boyes)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Request for information - front-ending IBM 7171 with CISCO ASM
Message-ID: <3615@brazos.Rice.edu>
Date: 12 Dec 89 05:44:09 GMT
References: <1076@ariel.unm.edu> <8912090646.AA16735@ucbvax.Berkeley.EDU>
Reply-To: dboyes@brazos.rice.edu (David Boyes)
Organization: Rice University, Houston, Texas
Lines: 63

In article <8912090646.AA16735@ucbvax.Berkeley.EDU> cire@CISCO.COM (cire|eric) writes:
>
>This sounds interesting.  What exactly is an IBM 7171 and how are you
>trying to connect the cisco to it?
>Eric B. Decker
>cisco Systems - engineering
>email:	cire@cisco.com

The 7171 is a protocol conversion box that provides IBM 3278
emulation for a large set of standard async ASCII terminals. It
grew out of a research project at Yale that eventually produced a
beastly gadget called a Series/1 that did essentially the same
job, but was much more difficult to configure and use.

The 7171 is essentially an industrial grade PC with a 370 channel
interface and up to 64 async ports (minimum 8, expandable in 8
port increments) running a embedded program that translates
keyboard input from popular ASCII terminals to the 3270-style data
streams that IBM mainframes expect. It also translates 3270 data
streams from the host into appropriate escape sequences for 
each type of supported ASCII terminal by doing lookup of
sequences stored in EEPROM. Users can add new terminal types by
running a configuration program on an ordinary IBM PC or PS/2 and
download the configuration into the controller via a serial line.

It's a very well-thought out box -- IBM did a good job with the
Yale research.

Some sites provide TCP access to their IBM boxes by attaching a
terminal server to the async ports on a 7171 and configuring the
terminal server to rotor between free ports, like this:


          |               |--------|
    net   |               |        |========
          |   |------|====|  7171  |========  large IBM iron
          |---| TS   |====|        |
          |   |------|====|        |
          |               |--------|

Users can then 'telnet' to the terminal server and be
automagically assigned a 7171 port w/o having to drag serial
cables all over the place (assuming their 'telnet' does a
reasonable terminal emulator that the 7171 can understand --
although 7171s can deal with terminals as dumb as ADM-3s, so it
doesn't have to be much). It's a pretty smooth setup, once you
get all the configuration stuff right in the terminal servers
*and* get the right cables and modem signals rigged between the
terminal server and the 7171.

My guess is that the original poster has probably set up
something very much like this and is having some problems getting
everything set up and working smoothly.


Disclaimer: I don't work for IBM. I just like the 7171 -- I've
            babysat several of them in different places, and
	    they're very well-behaved. 8-)
-- 
David Boyes      "... no love was left; All Earth was but one thought - and
dboyes@rice.edu   that was death Immediate and inglorious; and the pang of
                  of famine fed upon all entrails - men Died and their bones
                  were tombless as their flesh ..."  - Lord Byron